Rotary drill



March 24, 1925. 1,530,803

w. A. ANDERSON ROTARY DRILL File'd Nov. 2'7, 1922 3 Shets-Sheet 1INVENTOR. Mil/AM .4. 4.4/oenscw BY I ATTQRNEYS.

March 24, 1925;

. 1,530,803 w, A. ANDERSON- ROTARY DRILL Fild '3 snets -shet 2 W. A.ANDERSON ,fnmw MM. 4 it/I16 4! March 24, 1925.

I I I I I l I I l I I l I I l l l l L I l l l I l IT Patented Mar. 24, 1925 I A HUNIIT-ED STATES WILLIAM ALEXANDER ROTARY DRILL.

To allaolzom it may concern:

Be it known'that I, WILLIAM ALEXANDER .ANDEnsoN, a citizen of the UnitedStates,

resident of San Francisco, county of San Francisco, State of California,have invented a new and useful Rotary .Drill, of which the following isa specification.

The present invention relates to improve-- lessen the labor of suchboring work, and to reduce the cost of the apparatus. It is a well knownfact that in the present practice of hydraulic rotary drilling the shaftcarrying the bit extends from the bottom of the well to the surface ofthe ground and a certain distance above the ground so that it maybedriven from a power plant which is supported independently of the shaft.In my device the power plant is brought into one unit with the shaft andmoves down-.

wardly with the same as the hole grows deeper so that it is unnecessaryto extend the shaft, a flexible connection being maintained between theshaft and the power plant carrying unit and the surface ofthe groundwhereby the unit may be pulled upward when it is desired to change thebit or when the intended depth 'has been reached. A further advantage ofmy device is that it becomes exceedingly easy to change the bits, and totake core samples of geological formations that the drill is passingthrough. In present day practice it happens quite frequently that thebit grows dull very quickly and its takes considerable time to changethe bit, increasing as the depth grows greater. My device comprises asingle unit connected to a hoisting apparatus above the ground by meansof a cable and a hose and its takes very little effort on the part ofthe men as well as very little time to lift the unit out of the well andreplace the bits or to take core samples of earth formation penetrated.A further object of my invention is to provide means whereby the dbrismay be removed from the bottom of the well with very littledifliculty,.my,

Application filed November 27, 1922. Serial No. 603,641.

(PATENT. .oFFI-cE;

AnnE'Iis'oN, or SAN mancisoo, oauronm. I

means being adapted for the flooding of the" dbris as well as for theremoval of the same by' air suction or pressure. The latter method isofparticular importance where water israre and where it is desired to makea close. study of the different strata passed by the drill.

With these and other objects in view I have illustrated the preferredform of my invention in the accompanying drawings, in which Figures 1,2, 3, 4. and 5 represent a vertical section through my device, Figure 1showing the top portion, Figures 2, 3 and 4 the central portion andFigure 5 the. bottom portion, Figure 6 a horizontal section taken alongline VI-VI of Figure 2, Figure 7 a bottom plan view, Figure 8 a verticalsection along line VII-VII of Figure 2, and Figure 9 a sectional detailview of an expansion chamber controlling the amount of oil contained inthe device. While I have shown only the preferred form of my invention,it should be understood that various changes or modifications might bemade,

within the scope of the claims hereto attached without departing fromthe spirit of the invention.

The housing (1) of my device comprisesa tube (2), an upper casting (3),closing the top of the tube and secured in its place by means of screws(4) and a lower casting (6) closing the bottom of the tube and securedin its place by means of screws (7). I prefer to drive my drill by meansof an electric motor and therefor have confined my illustrations to;that particular drive although it will be readily understood that, othermeans for driving my drill may be used such as compressedair. Aparticular feature of my invention is that I use two concentric shaftseach, of which carries'a bit of its own and both of which are rotatedsimultaneously but in opposite directions at-the same or differentspeeds. These two shafts are run by the same motor or motors, one ofthem being connected with the armature of the motor while the other isdrivenby the field, both of which are rotatably mounted in the housing.Referring to the drawings it will be seen that the inner shaft (8) whichis coupled in several places as at (8') and (8") extends from the uppercasting downwardly through the bottom casting and carries below saidbottom casting the bit (9 while the outer shaft (11), coupled-as s ownat I (11) and (11") surrounds the inner shaft concentrically so as toleave sufiicient space between the same for the different windings andother devices hereinafter to be described and narrows at the bottom asshown at (12) so as to make a running fit on the inner shaft when itpasses through the lower casting. The outer shaft also carries at thebottom a bit (13) disposed concentrically relative to the bit (9). Theinner shaft is held in proper alinement by its engagement with t e upperand lower castingsaswell as by suitable guldes (14) provided withanti-friction bearings (16).- The outer shaft is maintained in itsposition by means of suitable guides 17) and anti-friction bearings (18)reducing the friction to a minimum. A suitable thrust bearing (19) isprovided below the body portion of the outer shaft to support therotating field and armature, and another thrust bearing (21) above acollar (22) to bear against a guide (20) for holding the shaft againstupward motion. It will be seen that suitable stufling boxes (24) areprovided in the top and bottom castings to prevent any leakages aroundthe shaft.

For driving the drill I preferably use one or more single-phase orpolyphase induction motors, the armatures (26) being .associated withthe inner shaft while the fields (27) form a part ofthe outer shaft.Suitable wire connections may be made by brushes (28) engagingcollecting rings -(30). It will be readily understood that if neitherthe armature nor the field are held stationary, both of them will undernormal conditions develop an equal tendency to rotate whenever electriccurrent is supplied. The rotation of the armature will be inthe'opposite direction to that of the field so that when the motor isworking the two bits (9) and (13) are rotated in opposite directions. Itwill be seen from Figure 5 that the bell shaped bit (13) surrounds thebit (9) and is set to out in the opposite direction. Looking at thedevice from below the inner bit cutson a rotation in aclock-wisedirection while the outer bell-shaped bit cuts on a counterclockwiserotation.

The inner shaft is hollow and extends, slightly reduced, throughtheupper casting, the upper portion being'threaded as at (33) to receivethe end of a hose not shown in the drawing. At the lower end of theinner shaft the bore extends through the upper portion of the bit (9)and finds two outlets (34) through the slanting sides (36) of the innerbit.

It has been noticed that under normal conditions the inner and outershafts have an equal tendency to turn in opposite directions. But itwill be understood that if one of the two bits carried on said twoshafts should meet with an obstacle such as a hard rock formation whichwould not affect the other bit this fact would have a natural tendencyto slow down the bit meeting with the obstacle and might even cause thelatter bit to become stationary, while the other bit would racecorrespondingly faster without doing any work. To overcome this Iprovide the device shown in Figure 6, by means of which the two shaftsare connected to each other in such a manner that they have to maintainthe same speed ratios. ThlS devlce comprises an internal gear (37)associated with the which latter is held against rotation by meansreferred to hereinafter.

As long as both shafts have a tendency to run at the same speed ratios,the pinions (39) idle between the two gears (37) and (38). But as soonas one of the shafts develops a tendency, due to a lighter load,torotate faster than the other one the pinions (39) become active andtransmit any excess power from the shaft running under a lighter load tothe other thereby assisting the latter and overcoming the obstaclereferred to. In this manner both shafts are always forced to rotate atthe same speed ratios and all the'power transmitted'to the shafts willbe utilized.

To prevent thehousing itself from rotating within the hole drilled Iprovide the device shown in Figure 1 comprising a yoke (42) secured tothe top casting (3) by means of screws (43) in the yoke (42) arepivotally supported a plurality of links (46), the outer ends of thelinks on either side of the yoke being joined by bars (47). The top endsof the bars are connected to a central head (48) by pivoted arms (49)and the head is provided with an eye (51) adapted to receive a cable orwire rope con-- nection not shown in the drawing, whereby the wholedevice may be lifted. As long as the device is supported by theattachment, which connects with a cable, the

bars (47) are drawn inwardly to the yoke,

which tendency, however, is opposed by the spring(52) surrounding thestem (53) extending downwardly from the head (48) through the top memberof the yoke. The spring bears against the underside of the top member ofthe yoke and a nut (54) threadedly engaging the stem so that the tensionof the spring may be adjusted. When the bits strike the bottom of thehole and the weight of the device is wholly or partially taken off thecable and the head (48), the spring (52) forces the bars (47') away fromthe yoke into contact with the wall of the hole whereby the whole deviceis prevented from rotating.

As a particular feature of mydevice, should be mentioned my oil system.To prevent the device from collapsing due to external pressures or tointernal pressures as well as to prevent leakages it is desirable thatthe space between the housing and the shafts be kept filled with oil orother fluid continuously. But since the oil may heatduringthe operationof the device it is at the same time necessary to provide means forallowing of expansion of the oil or fluid. For this purposeI provide theexpansion chamber (56) shown in detail in Figure 9 which consists of atubular cup (57)- terminating at the bottom in a threaded nipple (58).adaptedto be screwed into the top casting(3) and communicating with apassage (59) extending through the casting. A cap (61) slidably engagesthe cup and is normally pulled downwardly by aspring (62). )Vhen the oilor fluid, which may be forced into the housing through any suitable holeas at (63) in the lower end of the housing (see Figure 4) expands, itforces the cap upward until the latter clears a. perforation (64) in thecup which allows any excess oil or fluid to run through the perforation(64). In this manner the housing is kept filled with'oil or fluidcontinuously without exposure to injury by internal pressure caused bythe expansion of the oil or fluid due to heat. Suitable means are provided which may consist of. adjustable spring or weight tension on thecap (61) which will maintain the oil or fluid pressure against externalpressures. This difference being under control by the above mentionedtension.

The operation of the device will be readily understood from theforegoing descrip tion. The whole device is suspended from a suitablederrick and the hose leading to the bore in the inner shaft as well asthe electric connections are wound on suitable drums so that all three,the lifting cable, the hose and the electrical connections, can followthe drill as the latter recedes from the surface. After the device hasthus been properly placed and begun to work hardly any further change isnecessary sinceino shafts need to be coupled and the device is limitedin its penetration only by the length of the cable holding it. .If itbecomes necessary to change the hits the whole device may be hoistedupward with very little loss'of time. To remove the dbris I either usehydraulic or pneumatic apparatus. The use of water does not involve anynew features and it may be 'ust briefly stated that the water is admittethrough the hose referred to, to the inside of the inner shaft pres bitsthereonfformed to attack the bottom of a well in opposite directions,electro-magnetic means causing relative rotary motion of'the two shaftsand compensating means causing both shafts torotate in predeterminedrelation irrespective of the load encountered byeither shaft.

2. In a rotary drill of the character described, two conc'entric'shaftshaving drill bits thereon formed to attack the bottom of a well inopposite directions, electromagnetlc means causing relativerotary motionof the two shafts andmeans associated with the two shafts formaintaining their respective speed ratio whereby power is transferredfrom oneto the other incase the latter is subjected to a heavier load.

In a rotary drill, an electric motor having a revolving field and arevolving armature, drill bits attached to the field and the armature, astationary casing surrounding the. motor, and compensating means for thefield and armature anchored to the casing for causing the field andarmature to revolve at a predetermined speed ratio irrespective of loadvariations.

4. In a rotary drill, an electric motor having a revolving field and arevolving armature, drill bits attached to the field and the armature, astationary casing surrounding the motor, a ring within the easinganchored to the same having pins extending from its face and pinionssecured to said pins and an internal gear associated with the field andan external gear asso ciated with the armature engaging said pinions formaintaining a predetermined speed ratio of the field and the armature.

5. In a rotary drill of the character described, a housing, a shaft anda motor actuating the same supported therein with freedom of rotarymotion, and means associated with the housing for automaticallymaintaining" and regulating internal 'presadjustable Ii sure of a fluidagainst external pressure, vsaid means comprising an expansion chambercommunicating with the housing, a cap slidably engaging the same,adjustab e ing means for seating the cap and an outlet normally coveredby the cap adapted to be cleared when'the internal pressure exceeds aredetermined de ee. In a rotary rill, an electric motor having arevolving field and a revolvm armature, drill bits attached to the fieland'the armature, a casing surrounding the motor, compensating means forthe field and armature anchored to the casing for causing the field andarmature to revolve at a predetermined speed ratio irrespective of loadconditions and means for holding yieldthe casing 11 ainst rotation madeto yield when upwar ull is exerted thereon.

8. In a sing e unit rotary drill comprising a casing, 21 bit carryingshaft rotatable therein and a ower lant r actuating the shaft mounte int e casing, means for holding the casing against rotation comprising aplurality of links pivoted to opposite sides of the casing, barsconnecting the extreme ends of the lmks on either side,

a central head, pivoted links connecting the

